Guinea's President Alpha Conde Wednesday said all of Africa was praying for Nelson Mandela, adding that he wanted the anti-apartheid icon to live "as long as possible".

The 94-year-old was admitted in a Pretoria hospital on Saturday for a recurring lung infection and was Wednesday said to be responding better to treatment after spending days in a serious but stable condition.

"What we want, and may God help us in this, is that Mandela lives for as long as possible," Conde told reporters in Paris during a visit.

"All of Africa is praying for him so that he returns to good health and emerges from hospital. Mandela is the pride of Africa, he is our icon. He represents the Africa we would like to have."

Mandela spent 27 years in prison during apartheid, walking free in 1990 before becoming South Africa's first black president four years later. He is the world's favourite elder statesman and widely viewed as its moral compass.